Sports Direct said on Friday that a review by law firm RPC into the role of Ashley's brother John in the business found he has been underpaid since the company floated in 2007.

"Had [he] been treated equally with other senior executives who helped to build the Company, he would, in fact, have received additional remuneration payments totalling c. £11m, which he was denied because of concerns at the time about public relations," Sports Direct said in a statement.

Sports Direct has called a general meeting on December 13 where it will ask independent shareholders to vote on the proposed payment. Mike Ashley, who owns just over half of the business, will abstain from the vote.

"I fully expect that independent shareholders will vote against this proposal due to the passage of time involved, although in my opinion, technically the money is owed and therefore should be paid," Ashley said in a statement.

"It's important for me to say that if John had owed one pound to Sports Direct, I would have ensured any sum was repaid in full. I hope shareholders will therefore be reassured that everything is in order and that any concerns are laid to rest."